Duodenal bulb plasma cells in duodenitis and duodenal ulceration

Decreased IgA+ plasma cells and IgA expression in acute liver necrosis mice

AIM: To investigate the number of intestinal immunoglobulin A (IgA+) plasma cells and expression of intestinal IgA in mice with acute liver necrosis.

METHODS: A model of acute liver necrosis was established by intraperitoneal injection of galactosamine (GalN) and lipopolysaccharide (LPS). Sixty mice were randomly divided into one of 4 equal groups: normal control, acute liver necrosis, LPS, or GalN. Hematoxylin and eosin staining, immunohistochemistry, and an enzyme-linked immunosorbent assay were employed to assess liver and intestinal injury, count intestinal IgA+ plasma cells, and measure the expression level of IgA and interferon γ (IFN-γ) in the small intestinal mucosa of mice.

RESULTS: Injured intestinal mucosa was observed in the acute liver necrosis group but not in the normal, LPS or GalN groups. Compared with the normal group, intestinal IgA+ plasma cells were slightly decreased in the LPS and GalN groups [429 ± 20 per high power field (HPF), 406 ± 18/HPF, respectively], whereas they were markedly decreased in the acute liver necrosis group (282 ± 17/HPF vs 495 ± 26/HPF in normal group, P < 0.05). The expression of intestinal IgA was also slightly decreased in LPS and GalN groups, but was markedly reduced in the acute liver necrosis group as determined by enzyme-linked immunosorbent assay (P < 0.05). In contrast, the level of IFN-γ was slightly increased in LPS, GalN and acute liver necrosis groups, but with no statistical significance (P > 0.05).

CONCLUSION: Intestinal IgA+ plasma cells and IgA expression levels indicating that mucosal immune barrier dysfunction, does exist in acute liver necrosis.

Ultrastructural changes in non-specific duodenitis

AIM: To investigate the ultrastructural and morphological changes of non-specific duodenitis (NSD) in an attempt to grade them according to the extent of the lesions.

METHODS: Biopsies were taken from the mucosa of duodenal bulb of 44 patients selected from the patients undergoing upper gastrointestinal endoscopy for epigastric discomforts. From each patient, two pinch biopsies on the same area were obtained from duodenal bulb. One was for scanning electron microscopy and the other was stained with hematoxylin-eosin, Warthin-Starry silver and both were then examined under light microscope. A total of 12 specimens (three from each degree of the normal and I-III of NSD diagnosed and graded by histology) selected from the 44 patients were dehydrated, critical point dried, coated with gold palladium and examined under a JEOL JSM-30 scanning electron microscope (SEM) at 20 kV.

RESULTS: According to the ultrastructural morphologic changes, non-specific duodenitis was divided into normal (as control group), mild, moderate and severe degrees according to results of SEM. The normal villi of duodenal bulb were less than 0.2 mm. There were inflammation cells, occasionally red blood cells and macrophages on the mucosal epithelial surface. Erosion and desquamation of epithelium could be seen. Three cases (25%, 3/12) had gastric metaplasia and Helicobacter pylori (H pylori) infection could be found in 5 cases (41.67%, 5/12) in duodenal bulb mucosa. The most distinctive feature was the ulcer-like defect on the surface of epithelial cells.

CONCLUSION: Non-specific duodenitis is a separate entity disease caused by different factors. SEM is of value as an aid in the diagnosis of mucosal diseases of duodenum.

Mucosal humoral immune response to Helicobacter pylori in patients with duodenitis

The humoral immune response to Helicobacter pylori infection in the duodenum has been investigated by short-term in vitro culture, ELISA, and immunoblotting techniques. H. pylori IgA secretion by duodenal bulb biopsies was significantly increased (P less than 0.001) in patients with duodenitis. The IgA response to H. pylori in patients with duodenitis was restricted to the first part of the duodenum; second part duodenal biopsies secreting significantly (P less than 0.001) less IgA during culture in vitro. H. pylori IgG antibody secretion by cultured biopsies was also significantly increased (P less than 0.01) in patients with duodenitis and those with gastric H. pylori infection but without duodenitis. Immunoblotting of duodenal bulb culture supernatants showed positive recognition by the mucosal IgA response of H. pylori antigens in the region of 120, 90, 61, and 31-26 kDa in patients with duodenitis. Serologically, such patients showed little evidence of IgA H. pylori antibodies by immunoblotting. These results demonstrate that the inflammatory response in the duodenal mucosa of patients with duodenitis represents a specific highly localized humoral response to H. pylori.

Quantitative histological study of mucosal inflammatory cell densities in endoscopic duodenal biopsy specimens from dyspeptic patients using computer linked image analysis

Inflammatory cell counting in endoscopic biopsy sections was carried out on duodenal mucosal samples from defined sites in patients with duodenal ulcer, duodenitis but no ulcer, non-ulcer dyspepsia, and asymptomatic controls using computer linked image analysis. The variables measured included polymorphonuclear and mononuclear cells per mm of superficial epithelium and per mm2 lamina propria. Duodenal ulcer crater margin and mucosal biopsy specimens from endoscopically inflamed mucosa in the group with duodenitis but no ulcer showed significantly higher inflammatory cell counts than endoscopically normal non-ulcer dyspepsia and control mucosa. Biopsy specimens from non-ulcer dyspepsia patients showed significantly higher lamina propria polymorphs than control group mucosa. Endoscopically normal duodenal ulcer and duodenitis but no ulcer mucosa also showed significantly higher acute and chronic inflammatory cell counts than controls. The prevalence of Helicobacter pylori in duodenal biopsy specimens was low (0-22%) and unrelated to local inflammatory response. Despite histological appearances, duodenal biopsy specimens from non-ulcer dyspepsia patients showed significantly higher inflammatory cell infiltration than control specimens, suggesting that at least some represent part of a spectrum of subclinical peptic disease.

Definition of gastroduodenal junction in healthy subjects

To study the appearance and distribution of the normal mucosa at the gastroduodenal junction in man, 14 specimens of normal mucosa, eight obtained during pylorplasty, and "relatively" normal specimens from the distal stomach and whole duodenum were examined microscopically. Three histologically distinct types of normal duodenal mucosa were found at this junction. These were termed antral type duodenal mucosa, transitional type duodenal mucosa (which is also referred to as gastric surface epithelial metaplasia), and jejunal type duodenal mucosa. Antral type duodenal mucosa appeared as a series of finger-like processes 1-3 mm long, circumferentially located around the junction of the antrum and duodenum; transitional type duodenal mucosa extended 2-3 mm beyond this; and the rest of the mucosa was jejunal type duodenal mucosa. The mucosa of the pyloric antrum can therefore lie adjacent to antral type duodenal mucosa, or adjacent to either of the components of transitional type duodenal mucosa.